True longitude

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In astrodynamics true longitude is the longitude at which an orbiting body could actually be found if its inclination were zero. Together with the inclination and the ascending node, the true longitude can tell us the precise direction from the central object at which the body would be located at a particular time.

[edit] Calculation

The true longitude $l\,$ can be calculated as follows:

$l=\bar{\omega} + \nu\,$

where:

$\bar{\omega}\,$ is longitude of orbit's periapsis,
$\nu\,$ is orbit's true anomaly.

v • d • e

Orbits

Types

General	Box · Capture · Circular · Elliptical / Highly elliptical · Escape · Graveyard · Hyperbolic trajectory · Inclined / Non-inclined · Osculating · Parabolic trajectory · Parking · Synchronous (semi · sub)

Geocentric	Geosynchronous · Geostationary · Sun-synchronous · Low Earth · Medium Earth · Molniya · Near-equatorial · Orbit of the Moon · Polar · Tundra

Other	Areosynchronous · Areostationary · Halo · Lissajous · Lunar · Heliocentric · Heliosynchronous

Parameters

Classical				Other
$i\,\!$	Inclination	$\omega\,\!$	Argument of periapsis	$\nu\,$	True anomaly	$L\,$	Mean longitude
$\Omega\,\!$	Longitude of the ascending node	$a\,\!$	Semi-major axis	$b\,$	Semi-minor axis	$l\,$	True longitude
$e\,\!$	Eccentricity	$M_o\,\!$	Mean anomaly at epoch	$\epsilon\,$	Linear eccentricity	$T\,$	Orbital period
				$E\,$	Eccentric anomaly

Maneuvers

Bi-elliptic transfer · Geostationary transfer · Gravity assist · Hohmann transfer · Inclination change · Phasing · Rendezvous · Transposition, docking, and extraction